DEY-EOT OF INCENSE CEDAE. 19 



decays caused by Trametes pini and by Fomes laricis (the chalky 

 quinine fungus) intermingled in the wood of living Douglas firs on 

 several occasions, while down logs in the woods are often mycological 

 gardens of wood-destroying fungi with the decays completely 

 intermingled. 



Both the dry-rot in small pockets and the Trametes pini decay are 

 nearly always found around decayed knots or following along healed 

 wounds, mainly those caused by fire. Where the infections occur 

 around knots the decay is almost invariably confined to the imme- 

 diate neighborhood of the knot, resulting in little or no loss in the 

 merchantable contents of the tree. Where any appreciable quantity 

 'of wood was rendered unmerchantable, the decays were almost 

 invariably in intimate connection with healed-over wounds caused 

 by fire, frost, or lightning, particularly the first, throughout their 

 extent. Exceptions to this rule did occur. In one tree, for example, 

 the Trametes pini decay extended for a distance of 23.5 feet in the 

 center of the tree above an open fire scar without being in connection 

 with any other wound. But the fire scar was very large, extending 

 deeply into the tree and undoubtedly had a far-reaching influence 

 on conditions in the heartwood. In another tree (tree No. 40 on the 

 intermediate area; see p. 17) this same decay extended for 22.1 

 feet in between two areas of typical dry-rot without following along 

 any wound. The dry-rot in small pockets was found in one instance 

 to extend for a distance of 8.2 feet, not in connection with a wound 

 but merely as an extension of typical dry-rot. This case has already 

 been cited (tree No. 392 on the intermediate area; see p. 18). 



The above fact suggests that the dry-rot in small pockets may be 

 the result of the influence on the dry-rot fungus of changed condi- 

 tions in the heartwood, either physical, chemical, or both, induced 

 by the presence of wounds or knots. 



In further support of this hypothesis, it is almost invariably the 

 rule wherever typical dry-rot is found along healed fire scars in the 

 butt of a tree that instead of the pockets of normal size, one or more 

 long continuous pockets of the dry-rot follow immediately along the 

 scar throughout its length and invariably run out close to the end of 

 the scar. A maximum length of 10 feet has been attained. Such 

 pockets have never been found except in connection with wounds. 

 This seems to prove that variations in the typical form of dry-rot 

 may be induced by certain types of wounds in the tree. 



The fact that the Trametes pini decay is usually found in the 

 immediate vicinity of knots or healed-over wounds may be taken to 

 indicate that incense cedar is an unsuitable host for Trametes pini 

 and that the organism can rarely progress much beyond the point of 

 infection. This would also explain the rare production of sporo- 

 phores and the fact that in the only known collection, to cite Weir's 



